Replacing a deck

Discussion in 'Wooden Boat Building and Restoration' started by Guest, Oct 31, 2003.

  1. Guest

    Guest Guest

    Well, this does look like the right place for my question. I'm considering buying a 40' Angelman designed ketch built in 1966. Her deck is now fiberglass over ply, which I'd like to replace with a deck that looks more like the original. I'd like to find out whatever I can about process/methods, and paticularly about materials. I assume the original deck was replaced because it leaked, a commom problem with old wooden decks. Are there any more modern construction methods and materials that address this problem, but that would still give me the look/feel of the original? My thought is ply covered by some type of wateproof membrane (is there such a thing that would work in this application?), then covered by a traditional deck. Any thoughts, shared experiences, recommended reading, would be most appreciated.

  2. mmd
    Joined: Mar 2002
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    Location: Bridgewater NS Canada

    mmd Senior Member

    Oh, Dennis! You have come here with a topic that provokes some pretty intense opinions. It may well be the precursor to the fall of Western civilization as we know it. There are about a hundred ways of laying a deck; about 10% are tried and true, and all are vehemently defended by their promoters. Not one to back away from such a melee, I'll cast the first stone:

    Composite decks on mid-size and up modern yachts are usually comprised of three layers: an interior non-structural liner, a structural core, and an exterior cosmetic/non-slip/waterproof surface.

    The interior liner is required for both cosmetic purposes and to provide some thermal and acoustic insulation. These range from painted tongue-and-groove softwood staving to glued-on foams & fabrics.

    The structural core provides the strength of the deck by resisting point loads, hull stresses, and the loads placed on deck hardware. Plywood is a popular material becuse of its inherant strength, provided that it doesn't become compromised by water ingress and subsequent rot.

    The exterior surface is the first line of defense for keeping water out, and while doing this it must provide good traction underfoot whether wet or dry, be long-wearing, and be attractive. A tall order.

    Usually there are compromises to be made when selecting the material & construction method to be used on any given deck. What is strong may be too heavy; what is watertight may be ugly. What looks good may be difficult to install without damage to the watertight integrity of the deck. This last one is the nightmare of teak decks laid on ply or balsa-core sub-decks, and the one that I shall address.

    My current favourite method (I'm always willing to entertain new methods and reserve the right to change my mind) of laying a teak deck on a composite core is as follows:

    1.) Cut & dry-fit a structural core deck (over a previously laid interior liner such as painted tongue-and-groove softwood staving, if required). Remove the fitted panels and epoxy-coat all surfaces. Permanently re-install core deck, making sure to bed it securely with appropriate goop and to re-epoxy any surfaces that have been cut or abraded.

    2.) Fill all screw-holes, seams, etc. in the core deck with epoxy and filler, and sand smooth.

    3.) Apply a layer of 8-oz fibreglass cloth set in epoxy to the surface of the core deck, making sure to bond the edges completely to the toerail or hull side (whichever is appropriate), and that there are no gaps or lumps on the core deck surface.

    4.) Layout the teak deck and install it by drilling and counterboring the screwholes in the traditional manner, but bed each plank in 3M 4200 compound (less adhesive than 5200 so repairs will be easier) and screw it down into place with cheap steel screws.

    5.) When the deck is complete and the 4200 has set, back out the screws and fill the screwholes with 4200 using a syringe, thereby restoring the watertight integrity of the core surface that you had punctured with those hundreds or thousands of screws. The 4200 compound bedding is now the unbroken adhesive membrane that bonds the teak deck to the core deck.

    6.) Bung the now empty screw holes in the normal manner, using epoxy instead of varnish as glue, because you don't have to remove the bung to remove a screw when replacing a plank. Sand the deck and pay the seams and you're done.

    I know of decks done in this manner that are now around ten years old and have spent most of that time in the tropics without failure or leaks, including one vessel that has circumnavigated. I am pretty confident in this process. I would suggest that the teak decking be at leat 3/8" thick (more is better) so that bunging is secure and so there is sufficient "meat" in the deck to absorb many years of abrasive wear and the occasional sanding-down.

    That's my opinion - I'll happily look forward to rebuttals and alternate suggestions.
  3. gonzo
    Joined: Aug 2002
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    Location: Milwaukee, WI

    gonzo Senior Member

    From what you say, the deck is in good shape. Lay teak strips on polysulfide and caulk in between. It will look like the original.

  4. Captn_Pea
    Joined: Oct 2003
    Posts: 5
    Likes: 0, Points: 0, Legacy Rep: 10
    Location: Spring Lake, Mi

    Captn_Pea Junior Member

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